1. Field of the Invention
The present invention relates to an in-plane switching mode active matrix liquid crystal display device that displays images by applying a voltage across an electrode pair in the direction substantially parallel to a substrate.
2. Description of the Related Art
In-plane switching mode has been increasingly employed in liquid crystal display devices. In-plane switching mode liquid crystal display devices display images by applying an electric field substantially parallel to an insulating substrate between a pixel electrode and a common electrode placed across from each other to align liquid crystals. The in-plane switching mode operation minimizes viewing-angle-based gray-scale inversion and deterioration in contrast ratio. In conventional in-plane switching mode liquid crystal display devices, however, there is only one path per pixel for a voltage to be supplied through a pixel electrode to a capacitor terminal. The capacitor terminal, connected to the pixel electrode, is placed opposite to a capacitor electrode with an insulating layer interposed therebetween to generate capacitance.
For example, a technique disclosed in Japanese Unexamined Patent Application Publication No. 2000-131714 and illustrated in FIG. 1 provides only one voltage supply path through the pixel electrode to the capacitor terminal in at least one pixel. Thus, if a pixel electrode line from a connection of the pixel electrode and a drain electrode to a connection of the pixel electrode and the capacitor terminal is disconnected due to contaminants generated during processing and so on, no voltage is supplied to the capacitor terminal, making it unable to generate the necessary capacitance. This causes defects such as display flicker.
For another example, Japanese Unexamined Patent Application Publication No. 2001-33814 and illustrated in FIG. 1 describes the structure in which the pixel electrode and the capacitor terminal are formed in the same conductive layer. This technique also provides only one voltage supply path through the pixel electrode to the capacitor terminal (which is referred to as a capacitor part in this publication) in at least one pixel. Thus, if a pixel electrode line from a connection of the pixel electrode and a drain electrode to a connection of the pixel electrode and the capacitor terminal (the capacitor part) is disconnected due to contaminants generated during processing and so on, no voltage is supplied to the capacitor terminal. It is thus unable to generate the necessary capacitance, producing defects such as display flicker.